Congratulations to Rob, the randomly-chosen winner of last week's "Win a Book" contest! Rob,we'll be in touch with more details very soon.

Our big presidential trivia project for the most recent election fell through, but let's share some of that fun information in today's Tuesday Test Time challenge here at the mentalfloss.com Brain Game. Good luck:

What factor, concerning their time in office,
do these six U.S. presidents (but no others) have in common?

George Washington, John Adams, Ulysses Grant,
Theodore Roosevelt, Herbert Hoover, Richard Nixon. 

Here is the ANSWER.

What factor, concerning their time in office, do these six U.S. presidents have in common?

George Washington, John Adams, Ulysses Grant, Theodore Roosevelt, Herbert Hoover, Richard Nixon.

ANSWER:  They were each in office during a period when no former POTUS was still alive.

Did you come up with a different (but correct) answer? Feel free to share it with us in the comments below. Thanks for playing!